The long term objective of this study is to determine what extragenetic contribution the mammalian spermatozoan provides the ovum. Using microinjection techniques, sperm components will be injected into mouse ova that have been parthenogenically activated. Special attention will be given to the midpiece-tail component of the spermatozoan to determine the possible contribution and fate of the paternal mitochondria. Although the inheritance of mitochondria appears to be solely maternal, in vertebrates the mitochondria of the spermatozoa enter the egg at fertilization and are detectable during early embryogenesis. To evaluate whether the molecular basis for maternal inheritance of mitochondria can be a preprogrammed deficiency of the male mitochondrial genome, the DNA sequence of several regulatory regions of the mitochondiral DNA from sperm and ova will be compared. These studies will help identify epigenetic and nuclear regulated processes that are essential for normal mammalian development. A better understanding of these events is necessary to explain how pertubations lead to birth defects. In addition a more detailed comprehension of the biochemical events at and following fertilization will provide necessary information to aid in the treatment of the infertile and may provide superior approaches to fertility control.